Coking oven

ABSTRACT

A coking oven has refractory walls surrounding at least one chamber and including a bottom wall of a material having a given thermal conductivity, a peripheral wall extending upwardly from the bottom wall and having a taller lower section of a material having a higher thermal conductivity and in its shorter upper section a thermal conductivity corresponding to the given conductivity. The roof is composed in part of the material having the given conductivity.

United States Patent 1191 Echterhoff Feb. 19, 1974 [54] COKING OVEN 1,818,713 8/1931 Hughes 202/223 2,147,681 2/1939 Van Ackersen.. 202/267 X [75] Inventor: Hemmh Echterhofi Essen 3,496,067 2/1970 Perch 202 267 x Germany 3,390,002 6/1968 Davies et al. 106/58 [73] Assigneez Firma Bergwerksverband' GJnJLH 3,676,163 7/1972 Mortl 106/58 Essen, Germany Primary ExaminerNorman Yudkoff [22] Flled: 1971 Assistant ExaminerDavid Edwards 21 APPL 19 420 Attorney, Agent, or FirmMichael S. Striker [30] Foreign Application Priority Data [57] i ABSTRACT Nov. 14,1970 Germany 2056119 A Coking Oven has refraflofy Walls Surrounding at least one chamber and including a bottom wall of a 52 U.S. c1 202/267, 202/223, 106/58 material having a given thermal conductivity, a p 51 Int. Cl Cl0b 29/02 ripheral Wall extending p y from the bottom Wall 58 Field Of Search 202/267, 223, 139, 270; and having a taller lower Section of a material having 10 /5 7 a higher thermal conductivity and in its shorter upper section a thermal conductivity corresponding to the [56] References Cit given conductivity. The roof is composed in part of UNITED STATES PATENT the material having the given conductivity.

682,441 9 1901 Wellman 202/267 6 Claims, 2 Drawing Figures PATENTEI] FEB I 9 I974 sum 2 0F 2 INVENTOR Ilavvmu scum win We? I COKING OVEN BACKGROUND OF THE INVENTION The present invention relates to coking ovens, and particularly to coking ovens with high specific throughput capacity.

It goes without saying that the higher the specific throughput capacity of a coking oven the more desirable such an oven will be within the prevailing attempts to increase oven output of such ovens. In recent years throughput was increased in coking ovens by increasing the height and length of the oven chambers while retaining the chamber width unchanged. However, this did not result in an increase of the specific throughput of the oven chambers inasmuch as an increase of this type can be achieved only by reducing the strength of the stretcher bricks and thereby increasing or improving the flow of thermal energy between heating flue and coal hopper. Other possibilities for increasing the specific throughput of the coking chambers are by increasing the heating gas temperatures or by using refractory materials for the oven lining which have better thermal conductivity than previously.

However, all of these possibilities which are of course already known have certain limitations. It is evident that the strength of the stretcher bricks cannot be reduced at will in order not to endanger the stability of the heating flue walls. On the other hand, increasing the heating gas temperatures reduces the life of the coking oven, results in increased thermal radiation and consequently thermal losses and may possibly lead to the development of ash during the coke pushing operation, in which latter case the ash may soften or even melt and will lead quite rapidly to a destruction of the refractory material. The last of the aforementioned possibilities for improving the specific throughput capacity of a coking oven chamber, namely to use linings composed of materials having higher thermal conductivity, involves an increase in the expenses of erecting the oven because at least at the present time these materials are substantially more expensive than for instance the known silica bricks. Nevertheless, the desire to increase the specific throughput capacity is such that all of these measures have been taken into consideration. Despite all this, the present state of the art is not as satisfactory as it could be.

SUMMARY OF THE INVENTION It is, accordingly, a general object of the present invention to provide an improved coking oven with high specific throughput capacity which avoids certain of the disadvantages attendent to the prior-art approaches.

More particularly, it is an object of the present invention to provide such an improved coking oven, utilizing special lining materials.

Still more particularly, it is an object of the present invention to provide such an improved coking oven using lining materials with different thermal conductivity factors but substantially equal coefficients of thermal expansion and contraction.

In pursuance of these objects, and of others which will become apparent hereafter, one feature of the invention resides in a coking oven with high specific throughput capacity which, briefly stated, comprises refractory wall means surrounding at least one chamher and including a bottom wall of a first material having a first thermal conductivity factor, a peripheral wall extending upwardly from the bottom wall and having a taller lower section of a second material having a higher second thermal conductivity factor and a shorter upper section of the first material, and a roof composed in part of the first material. Heating flue means are provided in the wall means for heating the contents of the chamber.

The invention is based upon the realization that contrary to previous practice it is advantageous to utilize in the erection of coking ovens made of refractory material refractory bricks or stones of differential thermal conductivity. In particular, the stretcher and header bricks are to be made, according to the present invention, of refractory bricks or stones having high thermal conductivity whereas the remaining bricks are wholly or in part of refractory bricks of lower thermal conductivity. This means that the bottom wall or sole and/or the heads adjacent the draw plugs and/or the wall portions in the region of the gas collecting space above the lower edge of the opening can be made of refractory material of lower thermal conductivity.

A coking oven constructed in this manner has the advantage that the sole, the head and the gas collecting space remain relatively cool with respect to the walls which are contacted by the coal. As a result of this, it is for instance avoided that excessively small pieces of coke develop on the sole, so that a coking oven constructed according to the present invention can be subjected to the coke-pushing operation without any difficulties even if the coking operation proceeds rapidly and the coking temperature is high.

If the heads are made according to the invention, that is of bricks of lower thermal conductivity there will of course be a smaller thermal flow between the header wall and the door frame as well as the buckstave. This results in a substantial lessening of stresses upon these portions of the oven, a further advantage of the present invention. In addition, the cooler gas collecting space that is cooler by reference to the prior art provides substantial advantages because the undesired graphite formation in the gas collecting space, is avoided due to lesser after-cracking of the oven gases.

In practical operation of the present invention it is advantageous to make the stretcher and header bricks which contact the coal in the oven chamber of material having a thermal conductivity of approximately 2.0-6.0 kcal/mh. C, preferably 3.45 Kcal/m.h.C. For the other parts of the refractory wall, refractory material with lower conductivity is used, namely a thermal conductivity of between approximately 1.0 and 1.8 kcal/m.h. C; certain parts of the wall may be made of the conventional insulating bricks having a thermal conductivity factor of O.2O.7, preferably O.30.5 kcal/m.h. C.

All known refractory bricks can be used for the purposes of the present invention as long as they have the desired thermal conductivity factor and are capable of withstanding the aggressive conditions of a coking oven I have found particularly advantageous for making the sole, the heads and the gas collecting space, refractory bricks of a good fire clay quality as well as sillimanite and silica bricks. The material for making the refractory wall means surrounding the heating flue, that is the stretcher and header bricks, may be made of the same materials as those just mentioned above, but with additives incorporated therein to increase their thermal conductivity such as metal oxides or metal carbides which afford higher thermal conductivity but at least approximately the same thermal expansion and contraction coefficient as the base material.

Refractory materials with a thermal conductivity factor below 2 kcal/m.h.C are for instance the well known fire clay bricks, for instance 42-45 percent A1 and 50-54 percent SiOZ; also suitable are silica bricks in excess of 95 percent SiO and sillimanite bricks (AIgOg Thermal conductivity in excess of 2 kcal/m.h.C is for instance possessed by artificial refractory magnesite bricks as well as magnesite bricks and the aforementioned bricks in certain metal oxides or metal carbides are incorporated namely 20-70, preferably 40-60 percent by weight of SiC or of oxides of the elements Fe, Ti, Cu, Ni, Co, Ta, Os and W0.

The novel features which are considered to be characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a vertical section through a coking oven according to the present invention; and

FIG. 2 is a fragmentary detail view shown approximately on double scale of FIG. I, ofa coking oven embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before entering into a detailed discussion of the drawing, it is emphasized that the disclosure herein assumes that the construction and operation of the coking oven and the location of the flues and other features attendant to such ovens are well known to those skilled in the art. They are not, in any case of importance for the purposes of the present invention which have been clearly disclosed herein and are set forth in the appended claims. If, however, additional information concerning these known features is desired, a detailed and valuable discussion of the construction and operation of coking ovens may be found on pages 102-121 of The Making, Shaping and Treating of Steel" 8th edition, a handbook issued by the United States Steel Corporation.

Discussing now the drawing in detail, and firstly FIG. 1 thereof, it will be seen that this Figure illustrates a vertical section through one coking chamber 1 of a coking oven, embodying the present invention, the coking chamber not being filled with coke. To the left and to the right in the drawing of the chamber 1 are the fines. In this Figure, the refractory bricks having a high thermal conductivity factor are shown in section with wavy section lines, refractory bricks with lesser thermal conductivity factor are shown dotted and known insulating bricks are shown in section with alternating continuous and broken lines. Reference numeral 2 in FIG. 1 identifies the header and stretcher bricks, reference numeral 3 the bottom wall of the chamber, and reference numeral 4 the part of the circumferential wall which surrounds the gas collecting space 5. Reference numeral 6 identifies the roof or ceiling of the oven. The composition of the various wall portions will be clear from the sectioning which has been employed.

In FIG. 2, I have illustrated a view of the refractory wall means of an oven which isbroken open approximately at the middle of its height, and it will be seen that half a coking chamber with a portion of the heating flue to the left of it, is shown. The sectioning of the materials again indicates the same conductivity factors whichhave been discussed above with respect to FIG. 1. Reference numeral 7 designates the bottom wall of the chamber which is overlapped by the door plug 8 which pivots out of the oven as the door 9 is opened. The door 9 and the door frame 10 are lined in conventional manner with insulating brick 11. Reference numeral 12 designates a so-called overhead binding brick which does not contact the contents of the chamber when the oven is in operation. The stretcher bricks l3 and header bricks 14 are of refractory material having high thermal conductivity in accordance with the present invention, as indicated by their hatching.

It will be appreciated that the invention is not limited to a particular oven construction per se, but is concerned with the utilization of refractory materials of different thermal conductivity factors, but of at least substantially identical coefficients of thermal expansion and contraction, in different parts of the wall means bounding the oven chamber.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.

While the invention has been illustrated and described as embodied in a coking oven construction, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the sirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features'that, from the standpoint of prior art, fairly constitute essential characteristics of the' generic or specific aspects of this invention and, therefore such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by letters Patent is set forth in the appended claims.

1. A coking oven with high specific throughput capacity, comprising refractory wall means surrounding at least one chamber and including a bottom wall of a first material having a first thermal conductivity factor, a peripheral wall extending upwardly from said bottom wall and having a taller lower section composed entirely of a single second material having a higher second thermal conductivity factor and a shorter upper section of said first material, and a roof composed in part of said first material; and heating flue means in said wall means for heating the contents of said chamber.

2. A coking oven as defined in claim 1, wherein said first material has a thermal conductivity factor of between substantially LO and 1.8 kcallm.h.C, and said second material has a thermal conductivity factor of between substantially 2 and 6 kcal/m.h.C.

6 3. 'A coking oven as defined in claim 2, wherein the 5. A coking oven as defined in claim 4, wherein the thermal conductivity factor of said second material is thermal conductivity factor of said third material is bebetween substantially 3 and 4.5 kcal/m.h.C. tween substantially 0.3 and 05 kcal/m.h.C.

4. A coking oven as defined in claim 2, said wall 6. A coking oven as define in claim 1, wherein the comeans including a third material having a thermal con- 5 efficients of thermal expansion of said first and second ductivity factor of between substantially 0.2 and 0.7 materials are substantially identical. kcal/m.h.C. 

1. A coking oven with high specific throughput capacity, comprising refractory wall means surrounding at least one chamber and including a bottom wall of a first material having a first thermal conductivity factor, a peripheral wall extending upwardly from said bottom wall and having a taller lower section composed entirely of a single second material having a higher second thermal conductivity factor and a shorter upper section of said first material, and a roof composed in part of said first material; and heating flue means in said wall means for heating the contents of said chamber.
 2. A coking oven as defined in claim 1, wherein said first material has a thermal conductivity factor of between substantially 1.0 and 1.8 kcal/m.h.* C, and said second material has a thermal conductivity factor of between substantially 2 and 6 kcal/m.h.* C.
 3. A coking oven as defined in claim 2, wherein the thermal conductivity factor of said second material is between substantially 3 and 4.5 kcal/m.h.* C.
 4. A coking oven as defined in claim 2, said wall means including a third material having a thermal conductivity factor of between substantially 0.2 and 0.7 kcal/m.h.* C.
 5. A coking oven as defined in claim 4, wherein the thermal conductivity factor of said third material is between substantially 0.3 and 0.5 kcal/m.h.* C.
 6. A coking oven as defined in claim 1, wherein the coefficients of thermal expansion of said first and second materials are substantially identical. 